Steam-boiler furnace



2 Sheets-Sheet 2.

(No Model.)

-- 0. D. O RVIS.

STEAM BOILER FURNAGE'. No. 524,029'. Patented Aug. 7, 1894.

UNITED STATES PATENT OFFICE.4

ORLAND D. ORVIS, OF CHICAGO, ILLINOIS.

STEAM-BOILER FURNACE.

SPECIFICATION forming part of Letters Patent No. 524,029, dated August7, 1894.

Application led August l24, 1893.

To a/ZZ whom it may concern:

Be it known that I, ORLAND D. ORVIS, a citizen of the United States,residing at Ohicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in' Steam -Boiler and otherFurnaces, of .which the ,following is a full, c'lear, and exactspecification.

This invention relates to improvements in steam boiler and otherlfurnaces for promoting combustion and draft, and more specifically inthat class of furnaces in which a boiler or other surface to be heatedis, by means of an arch or arches, isolated from cold air conducted tothe fire chamber for promoting combustion and draft, or unavoidablyadmitted thereto while raking down and firing, and also isolated fromdirect exposure to a bed of incandescent fuel on the grate bars whetherburned or refractory fuel is used thereon.

The importance of my invention and the thereby securing of the objectshereinafter stated, may be appreciated when it is borne iny mind thatcomplete combustion and rapid draft in the presence of each other, arethe essentials to a successful furnace, and that complete combustion inthe absence of rapid draft reduces the efficiencyA of a furnace topractically the same degree as does incomplete combustion in thepresence of rapid draft.

Absolutely complete combustion as nearly as may be obviously'occurs indowndraft furnaces when properly operated, because all of the evolvedproducts of combustion must pass downwardly through the bed ofincandescent fuel onthe grate bars before escaping from the fire chamberwhereby they are maintained in the presence `of the necessary degree ofheat for and fully igniting them, but it is.' equally obvious that whatis gainedby com pletecombustion is substantially lost in the operationof the furnace owing to the unavoidable retardation of the draft due toconducting the products of combustion downwardly through theincandescent fuel before their escape into vthe updraft passager-*alziWith all of the advantages of v.operation gained in a downdraft furnaceby having the updraft passage lengthwise of and adjacent to the firechamber as' shown and described in' Serial No. 483,971. (No model.)

t my joint patent, No. 486,122, granted November 15, 1892, and my solepatent, No. 503,214, granted August l5, 1893, there is still an absenceof rapidity in draft and combustion to a degree rendering such furnacesvobjectionable when it is desirable to have the highest degree 'of heatdiffused with maximum rapidity over a steam boiler or other surface tobe' heated.

f Rapid draft exists almost without limit in updraft furnaces, butperfect combustion is impossible therein for that owing to this rapiddraft a substantial portion of the evolved products of combustion aredischarged from an igniting degree of heat before they have time toignite, and are thence swept over the bridge wall and escape from thefurnace without being utilized.

The securing of the rapidity of draft of an which the updraft passage isat the rear end updraft furnace in down draft furnaces in j I of the rechamber would be a substantial advantage, but obviously nevertheless anadvantage not to be compared `with that of `se.- curing such a draft ina down draft furnace wherein the updraft passage is lengthwise of andadjacent to a single tire chamber structure because of the shorter,freer and quicker discharge into said updraft passage of the ignitedproducts from the tire chamber in the l latter construction as comparedwith the'former, to say nothing of the increased boiler .l

surface to which draft heat is directly applied by the latter.

Now while myinvention includes the combining with all classes of downdraft furnaces a so3called direct draft passage, it is obvious or willbe later on, that in no single-arch structure having an updraft passagecan combustion be absolutely complete because at best a small portion ofthe products of combustion will be swept out of the fire chamber withoutignition, and hence some means must be provided for their ignition at apoint beyond the fire chamber if absolutely complete combustion in thepresence of rapid draft is to be secured. Absolutely complete combustionin the presence of this rapid draft however, may be secured by the useof a double fire chamber structure having lengthwiseof, adjacentto andbetween said chambers an updraft passage, owing to the fact that allyroe products of combustion escaping unignited from the fire chambersmust pass through the combined heat and flame of both fire cham berswhile impinging againstreach other in the updraft passage, and'inevitably thereby be fully ignited before contact with the surface tobe heated as is demonstrated by the practical operation of furnacesembodying the invention disclosed herein.

My invention therefore still more specifically relates to that class ofdown draft furnaces in which two fire chambers are employed, betweenwhich lire chambers, lengthwise thereof and adjacent to which is anupdraft passage through which all products of combustion from both firechambers must escape to a steam boiler or other surface to be heated.

'lhe object of my invention generally stated is to combine in a furnaceall the advantages of botha so-called down draft furnace and an updraftfurnace without including in such structure any of the disadvantages ofeither, or in other words, to combine in a furnace all of the advantagesof the perfect combustionA in a down draft furnace and the rapid draftof an updraft furnace. l,

More specifically stated, the object of my invention is to provide forconducting the products of combustion evolved and ignited in an archinclosed fire chamber from Without the same to the updraft passage of afurnace without passing them downwardly through the incandescent fuel,but in such a manner that they shall be rapidly broughtin contact withincandescent fuel on the grate bars immediately prior to their escape soas to insure their more nearly complete ignition.

Another object is to provide for conducting products of combustion froma double lire chamber of arched construction without passing saidproducts through the bed of in-v candescent fuel but in rapid and directcon* tact therewith, and directly to an updraft passage lengthwise of,adjacent to and between said fire chambers whereby the resultantimpinging of the flames and combining of the heat discharged from bothfire chambers shall ignite all products of combustion escaping fromeither of said fire chambers unignited.V

I attain these objects by features illustrated in the accompanyingdrawings, in which- Figure 1 represents a longitudinal section` of afurnace on line 1--1 of Fig. 2 embodying my invention showing its use inconnection with a steam boiler. Fig. 2 is a transverse section of thesame on line 2--2 of Fig. 1. Fig. 3 is a longitudinal sectional view online 3 3 of Fig. 4, of a steam boiler furnace embodying my inventionwherein the fire chamber is inclosed by a water arch connected with theboiler, and Fig. 4 is a transverse section of the same on the line 4:--4of Fig. 3.

Similar letters of reference indicate similar .A A indicate the sidewalls of a furnace of the usual construction provided with an ondinarydoor or doors B, ash pit door or doors C and one or more grate surfacesD, which grate surfaces are separated by a wall E rising from the bottomof the ash pit toa plane with the upper surface of the grate bars andextending, from the front wall of the furnace to a bridge wall F, but itwould be no substantial departure from my invention t''bmit the wall Eand have the grates contiguous to each other.

As shown in the drawings the grate surfaces are spanned by arches Gclosed at their rear ends by the bridge wall F which said arches jointhe side walls AAof the furnace, but at their opposing sides areseparated by an updraft passage H which extends `the length of thearches or iire chamber and is adjacent thereto and is the common andonly updraft passage for the products of combustion of both firechambers. These archesare supported in their operative positions in anysuitable manner as for example, at one. end by the bridge wall and atthe other end by the front wall of the furnace, and are closed at theirrear ends bythe bridge ywall F as shown, but may-have closed ends oftheir own. Between the adjacent side edges or bases of these arches andthe grate bar surface is a discha'rge passage I through which theproducts of combustion are discharged from the re chamber into theupdraft passage which said discharge passage preferably extends theentire length of the fire chamber and is of such a depth as topermitafree discharge of the products of combustion from the firechamber to the updraft passage and at the same time, deflect saidproducts against the incandescent fuel adjacent thereto to in sure asnearly as possible the ignition of such products by contact with thesurface of incandescent fuel, or in other words, to pass said productsover the surface of the incandescent fuel in sheets sufciently thin toinsure their ignition to the highest degree co`nsistent with a perfectfreedom of their discharge from the tire chamber to the updraft passage,and also to prevent cold air admitted to the fire chamber in firing fromchillingthe crown. sheets of the boiler or other surface to be heated,and any substantial volume of ignited products escaping from the tirechamber to the updraft passage.

In Figs. l and 2 the arches are shown of a solid construction with theoutside bases of the arch supported byledges a in the furnace wall andat their inner edges by bars b which may be embedded in the archstructure to better protect them from the destructive influences ofdirect heat, but said arches may be supported in any other suitablemanner and be constructed of any materialcommonly employed or adaptedfor such purposes.

In Figs. 3 and 4 the arches are of a hollow construction, preferably ofsteel, but may be of any other material so as to form a water chamberconstituting a water arch c over the IIO IZO

fire chamber and connected with the boiler by pipes d e at opposite endsthereof as shown in Fig. 3, so arranged that a perfect circulation ofwater between the arch and boiler is maintained, and the arches utilizedas asupplementary heating surface for water, but the water heated insuch arch may be used'for any other purpose when the boiler is not usedin connection with a furnace of my present invention.

The employment of the water arch in the manner shown and described ishowever the preferred construction for steam boiler purposes for thereason that the water heating surface of the steam boiler furnace ismaterially and substantially increased and the direct heat of the iirechamber is utilized for heating boiler water without any possible injuryto the boiler, and besides such a circulation of water is maintained inthe boiler that injurious precipitations and coating of the boilerthereby are substantially less than when no circulation exists.

In the practical operation of my furnace with an incandescent bed ofburning or refractory fuel on the grate surfaces the products ofcombustion evolved or ascending through said incandescent bed as may be,rise in the chamber forfned by the arches and then, owing to the draft,are caused to descend through the discharge passage I and impingeagainst each other in the updraft passage H,` the depth of the dischargepassages as before stated, being such that as far as possible allunignited products shall be brought in contact with the surface of theincandescent bed of fuel immediately prior to their discharge throughthe passages I.

An extended practical operation of my furnace however demonstrates thata maximum degree of rapid draft is not secured without a small portionof the products of combustion escaping unignited from the re chamber,but that by having the flames of double fire cham.- bers impin ge in theupdraft passage as before described and particularly at the moment oftheir discharge from the fire chamber, a degree of heat is producedthrough which none of the products of combustion can escape withoutbeing ignited, and hence, that by the use of the double lire chamberstructure with an updraft passage common to both and arranged betweenand lengthwise of said chambers, the result is absolutely completecombustion with a maximum rapid draft in the presence of each other, andtherefore that I am enabled by my furnace to supply heat to a steamboiler or other surface to be heated to the best advantage and withmaximum economy. In this connection it is proper ,to observe that thisadvantage and economy accrue to the use in the tire chamber of liquidand gaseous fuel as well as solid fuel as will be understood by bearingin mind that ignited products of combustion Whether from solid liquid orgaseousfuels, will, when ig nited, rise in the fire chambers, anddescend thence through the discharge passages thereof and impingeagainst each other in the updraft passage precisely the same, andtherefore that in the operation of my furnace with any of these fuels,complete combustion in the presence of rapid draft being the result, myinvention is not limited to the use of burning fuel on the gratebars asmight possibly be inferred from the construction shown.

While the double fire chamber structure vand the intermediate updraftpassage common to both have the advantage of diusingthe heat from thecenter simultaneously to both sides of the surface to be heated and alsothat ofsuch an impingement ofthe heat and ames of both iire chambers asto render combustion absolutely complete, it would be no departure frommy invention to employ a single arch fire 'chamber with a draft passageadjacent to and extending lengthwise of one or both sides thereof, norto have a tire chamber discharge passage between the grate surface andthe end edge of an arch inclosing the fire chamber in a furnace whereinthe updraft passage as may be, that the natural draft in and through thefire chamber is substantially asl rapid as in any updraft furnace,' thatit will burn the cheapest soft coal and waste coal without producingsmoke at the chimney,

that it will diffuse a greater number of a given number of units of heatover the 'surface to be heated with better effect than any otherstructure even when such other structure is provided with an artificialor forced draft, that it will more quickly heat and evaporate a greaternumber of pounds vof water with a pound of coal than any other furnace.

In conclusion it may also be observed that i in a furnace of myinvention the draft and the application of heat to the steam boiler orother surface to be heated are so full and complete that there is solittle radiation of heat against the front of the furnace and even fromthe fire chambers during firing that a fireman experiences no discomfortwhen standing even for an unusually prolonged time immediately in frontthereof, when with all other furnaces so heretofore employed theradiation of heat fromthe front of the furnace when standing at the samedistance is unbearable for a comparatively short time, and theimportance of thisabsence of radiation vfrom the front of a furnaceembodying' my inventionincreases as the number of furnaces are increasedin the battery, and as unavoidably or otherwise ventilation in theboiler room is decreased.

. Having thus described my invention, what Iclaim as new therein, anddesire to secure by Letters Patent, is

1. In a furnace the combination of an arch, a grate surface spanned bysaid arch and a dischargepassage at one side only of said arch and at apoint between the lower edge of the arch and said grate surface,substantially as described.

2. In a furnace the combination of an arch, a grate surface spanned bysaid arch, a discharge passage at one side only of said arch at a pointbetween the lower edge of the arch and grate surface, and an up draftpassage adjacent said discharge passage, whereby all the rising productsof combustion `must de-` scend in the fire chamber and discharge intothe said up draft passage in a plane above the surface of the grate barsand substantially1 below the crown of the arch and thereby be subjectedto a draft of maximum rapidity and maintained in an igniting degree ofheat a sufcient time for the ignition of substanf tially all saidproducts, substantially as described.

y 3. In a furnace, the combination of an arch, a grate surface-spannedby said arch, and a discharge passage at one side only and extendinglongitudinally of said arch which said discharge passage is at a pointbetween the lower edge of said arch and the grate surface,

whereby a discharge passage of .maximum` length and minimum depth isprovided for the tire chamber and all of the risin g products ofcombustion therein are caused to discharge in a thin sheet from the firechamber in a plane with or above the grate surface and substantiallybelow the crown of the arch, substantially asand for the purpose setforth.

4. In a furnace, the combination of two or more arches, grate. surfacestherefor spanned by said arches, discharge passages at one side only ofeach of said arches and at apoint between the lower edges thereof andtheir respective grate surfaces and up draft passages adjacent saiddischarge passages, substantially as described.

5. In a furnace, the combination of arches arranged side by side, gratesurfaces spanned bracing individual grate bar surfaces, circulatingwater arches inclosing the fire chamber, and an updraft passagelengthwise of and between said arches, in combination with a firechamber discharge passage directly connected with said updraft passage,which said discharge passage is substantially below `the crown or top ofthe fire chamber and in a plane with or above the grate bar surface,whereby a water arch furnace ,structure is subjected to the heat ofperfect combustion in the presence of a maximum degree of rapid'draft,sub stantially as described.

7. In a furnace, a double fire chamber embracing individual grate barsurfaces, circulating water arches inclosing the re chamber, an updraftpassage lengthwise of and between said arches, and a steam boilerconnected with said arches in combination with a re chamber dischargepassage directly connected with said updraft passage which saiddischarge passage is substantially below the crown or top of the rechamber and in a plane with or above the grate bar surface whereby awater arch furnace structure is subjected to the heat of perfectcombustion inthe presence of the maximum degree of rapid draft,substantially as described.

8. In a furnace the combination of the arches G G, grate surfaces D D,spanned by said arches, discharge passages I I at one side only of saidarches, and at a point between the lower edge of the arches and thegrate surfaces, and the up-draft passage H between and extending theentire length of both of said arches, substantially as and for the purpose described. i

ORLAND D. ORVIS. Witnesses:

J No. G. ELLIOTT, EDNA B. JOHNSON.

